The purpose of this study was to compare premenarcheal athletes (A) and nonathletes (NA) in terms of body composition and sexual maturation and to discern the relationship between these variables. Percent body fat (%BF) was determined by the three-component system of Siri utilizing body density from hydrostatic weighing and total body water measured by deuterium oxide dilution. Sexual maturation was self-assessed using the system described by Marshall and Tanner. ANOVAs and polynomial regression analysis revealed that both the A (N = 73) and NA (N = 53) showed similar values and linear increases (P < 0.001) in height (HT), weight (WT), breast (B) and pubic hair (PH) development from 7 to 15 yr but not in %BF ([Latin capital letter X with macron above]A = 15.7 +/- 4.6; [Latin capital letter X with macron above]NA = 20.5 +/- 6.4 (P < 0.001)). The NA exhibited a quadratic curve (P < 0.01) in %BF over age, while the A showed a negative linear relationship (P < 0.001) with age. Scheffe post hoc tests revealed significant differences (P < 0.03, A < NA) at 11 and 12-15 yr. When %BF was compared to maturation, the A were found to have less fat (P < 0.01) at stages 1 and 4 of PH and at stages 2, 3, and 4 of B. There were no significant differences between A and NA in the age at which B2, 3, or 4 or PH2, 3, or 4 occurred. Both groups exhibited similar and significant correlations between age, HT, WT, B, and PH development but not %BF. Partialing out age reduced the value of most correlations, but partialing out %BF had no effect. It was concluded that sexual maturation of the A was not impaired despite low %BF values.
(C)1991The American College of Sports Medicine